Eigenvalues and eigenvectors of square positive matrices are described by the Perron–Frobenius theorem. The trace and every row and column sum/product of a nonnegative matrix is nonnegative. Seamless ...
Physicists like to study all sorts of simplified situations, but here’s one I haven’t seen them discuss. I call it an ‘energy particle’. It’s an imaginary thing with no qualities except energy, which ...